Cash, Cash Equivalents and Investments - Summary of Fair Values of Cash, Cash Equivalents, and Short-Term Investments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	$ 62,152	$ 47,140
Short term investments	73,548	48,650
Long term investments	60,133	16,763
Fair Value on Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	64,246	51,214
Short term investments	73,548	48,650
Long term investments	60,133	16,763
Fair Value on Recurring | Cash
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	2,094	4,074
Fair Value on Recurring | Money Market Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	61,172	30,054
Fair Value on Recurring | Repurchase Agreements
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents		15,000
Fair Value on Recurring | Certificates of Deposit
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents	980	985
Short term investments	31,168	15,428
Long term investments	7,148	3,633
Fair Value on Recurring | Corporate Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Total cash and cash equivalents		1,101
Short term investments	32,432	24,552
Long term investments	48,680	13,130
Fair Value on Recurring | Commercial Paper
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short term investments		1,096
Fair Value on Recurring | Municipal Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short term investments	1,838
Long term investments	1,223
Fair Value on Recurring | Government Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Short term investments	8,110	$ 7,574
Long term investments	$ 3,082